Kava plants, a type of pepper plant also known as Piper methysticum, arc generally found in Polynesia, Melanesia, and Micronesia. The kava plant contains high concentrations of kavalactones (sometimes referred to as kavapyrones), including kavain, methysticin, yangonin, dihydromethysticin, desmethoxyyangonin, and dihydrokavain, and has been used as an herbal medicine. The prized part of the kava plant is the root system because it contains the highest concentrations of the active kavalactones. Kavalactones are also found in other parts of the plant. General information about kava plants can be found in Vincent Lebot, et al., “Kava The Pacific Elixir, The Definitive Guide to its Ethnobotany, History, and Chemistry”, Inner Traditions Intl. Ltd. (March 1997).
After a kava plant is harvested, the root is conventionally processed to generate a consumable product. In conventional and historical methods, the root is dried and ground to a powder. This powder contains not only the kavalactones but also plant oils, resins, and other substances. The powder can be mixed with water to form a beverage. The resinous ground dried root can also be packaged into capsules or other forms of delivery.
The effects of ingesting kava root extract will vary from person to person. Common effects include a state of relaxation and a reduction in muscle tenseness. Kava root has also been used to help sufferers of insomnia. It can also produce a mild state of euphoria. The ratios of the various kavalactones in the consumed product has a large impact on the effect experienced by the user.
There are a large number of different kava cultivars, each of which has differing ratios of the different kavalactones. Through historical knowledge and experimentation, various kava cultivars have been classified according to their effect, such as “daily” or “one-day”, “custom”, “two-day”, “medicinal”, and “no drink”. “Daily” kava cultivars are generally consumed daily and have relatively short-term effects. “Custom” kava cultivars tend to be used for ritual and ceremonial purposes. “Two-day” kava cultivars tend to have pronounced physiological effects and are known as “two day” because the drinker is usually affected for two days. “Medicinal” kava cultivars are specific for the treatment of ailments like rheumatism. “No Drink” kava cultivars are not recommended for consumption because they tend to induce nausea and other undesirable effects.
More recently, there have been concerns associating kava with occurrences of liver damage, although these reports are primarily anecdotal. Studies done in the 1970s and 1980s have found that “two day” kava cultivars have particularly high concentrations of methysticin and dihydromethysticin. These kavalactones contain a methylenedioxyphenyl functional group which, when activated through metabolic activity, forms intermediary compounds that can inactivate multiple P450 enzymes. There are some suggestions that inhibition of P450 enzymes can interfere with the metabolism of many pharmaceuticals. The solution proposed in the prior art is the development of new kava cultivars with reduced amounts of methysticin and dihydromethysticin and increased kavain content.
One of the most highly prized kava cultivars is a one-day cultivar that grows in Vanuatu. Relative to other cultivars, this cultivar is naturally low in methysticin and dihydromethysticin and has a proportionally higher concentration of kavain. However, this cultivar is not widely grown or available and most commercially available cultivars have increased levels of methysticin and dihydromethysticin and lower concentrations of kavain. Although breeding of new cultivars that can be widely grown and which have lower concentrations of methysticin and dihydromethysticin and increased concentrations of kavain is possible, this can be a time consuming process and is not assured of success. In addition, the kavalactones suspected of producing toxic effects when consumed by humans are also toxic to various insects and microorganisms, such as fungi. Thus, the hardiest cultivars are generally those which are least suitable for human consumption.
In a kava extraction process, the rate at which various kavalactone components are extracted varies according to the extraction solvent and extraction conditions used. However, kava root extracts are conventionally sold based upon total kavalactone content. Thus, the focus of conventional commercial extraction techniques has been to extract as much of the kavalactone content from the root source as possible and knowledge regarding different rates of extraction for different kavalactones is used to adjust the extraction process or select appropriate extraction steps to provide for the greatest total kavalactone extraction.
Various extraction techniques have been used to process kava root. Such techniques include the use of supercritical carbon dioxide (CO2) extraction, fluorocarbon extraction, and the use of various other organic and non-organic solvents to remove the kavalactones from the dried root. The resulting bulk extract is in the form of a paste.
Supercritical CO2 processes have been found to extract the largest quantity of kavalactones from the root and thus conventional practice has been to focus on the use of supercritical CO2 to extract all of the kavalactones from the root in the production of kava extracts. As will be appreciated, bulk extracts of substantially all of the kavalactones in the root will generally contain kavalactones in the same or nearly the same proportions as present in the source root. Because of the differing effects produced by variations in the kavalactone ratios of different cultivars, producers of such kava products are limited to specific kava cultivars as source materials in order to produce a kava product that produces a desired effect.
To the extent that the distribution profile of the various kavalactones in the extract have been of concern, conventional practice is to use additional processing steps, such as high pressure liquid chromatography (HPLC), to extract individual kavalactones. For example, HPLC and other chromatographic techniques, such as “flash” chromatography, have been used to process bulk kava extracts to isolate individual kavalactones. This process is cumbersome to implement and requires the use of machinery that is bulky and expensive to operate. Methods for extracting and purifying kava, including supercritical CO2 extraction and chromatography, are discussed in PCT publication WO 00/72861 to Martin et al. entitled “Pharmaceutical Preparations of Bioactive Substances Extracted from Natural Sources.”It would be advantageous and is an object of the present invention to provide a method of processing kava to provide an extract of kava as a paste, powder, or in other forms, and which allows the kavalactone profile to be altered during processing so as to have reduced levels of methysticin and dihydromethysticin and increased levels of kavain and dihydrokavain. It would be additionally advantageous if such techniques allowed the production of a processed kava product that had a kavalactone profile similar to (or improved upon) that of the most preferred “one-day” cultivars from Vanuatu by using a kava feedstock from a less desired cultivar. There would be yet a further advantage if such an altered-profile kava product could be produced using a minimal number of processing steps and without requiring additional processing, such as via chromatography, to isolate each individual kavalactone from the extract and then recombine the isolated kavalactones as appropriate.
There has been widespread use of bulk kava paste extracts as dietary supplements, e.g., mixed in drinks or packaged in capsules. Because kava paste is not always well suited for processing into consumable form or for distribution, e.g., as a dietary supplement, it would also be advantageous to produce a dry flowable kava powder. The powder can be distributed as is or further processed, e.g., to produce kava tablets.
When consumed, kava is typically swallowed. The kavalactones then pass through the stomach and intestines as they are absorbed into the bloodstream. It can take a relatively long time for the body to process kava and the effect of the ingested kavalactones can then be further diminished as the compounds are processed by the liver. It would therefore also be advantageous to deliver kava in the form of a rapid-dissolve tablet which would permit the kavalactones to be absorbed orally.